What ointment to apply to blistered lips is mainly treated according to what causes the blistering. If it is caused by local skin allergy due to contact with certain allergens, in addition to blisters, it may be accompanied by local skin redness, swelling, itching and other symptoms. Treatment may include the application of anti-allergy creams such as dexamethasone acetate cream, and oral anti-allergy medications such as cetirizine, loratadine, and vitamin C for symptomatic treatment. If the herpes virus is the cause, you can apply acyclovir ointment and take acyclovir tablets for antiviral treatment. If the herpes is caused by inadvertent burns, the main treatment is to apply scald ointment Kyowa Red Ointment.